Four neutral vinyl sulfones, two of which are paired with phosphonate groups, are described. The compounds are diisopropyl (2-phenylethenylsulfonylmethyl)phosphonate, C(15)H(23)O(5)PS, (I), diisopropyl {[2-(7-methoxy-1,3-benzodioxol-5-yl)ethenylsulfonyl]methylsulfonylmethyl}phosphonate, C(18)H(27)O(10)PS(2), (II), bis(trans-2-phenylethenyl) sulfone, C(16)H(14)O(2)S, (III), and bis(trans-2-phenylethenylsulfonyl)methane, C(17)H(16)O(4)S(2), (IV). Their structures can be considered as highly functionalized mimics of mono-, di- and triphosphates. These phosphate isosteres are currently of interest as agents for enzyme inhibition in both cancer and HIV therapy. All except one of the compounds has Z' > 1. The lone exception is (IV), a disulfone with twofold crystallographic symmetry. Geometrically, the sulfone functionality is found to be a good mimic for phosphate. The principal effect of the vinyl group is to shorten the S-C(vinyl) distance relative to the S-CH(2) distance by ca 0.05 A. The S-C-S and S-C-P backbones resemble the P-O-P backbone but are not identical because the S-C and P-C distances are longer than the P-O distance and the S-C-S and S-C-P angles are more acute than the P-O-P angle. No prior crystal structures of comparable compounds have been published.